Crystal structures of the phosphorylated BRI1 kinase domain and implications for brassinosteroid signal initiation.
Crystal structures of the phosphorylated BRI1 kinase domain and implications for brassinosteroid signal initiation.
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DOI：
10.1111/tpj.12445
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发表时间：
2014-04
期刊：
影响因子：
--
通讯作者：
Hothorn M
中科院分区：
文献类型：
--
作者：
Bojar D;Martinez J;Santiago J;Rybin V;Bayliss R;Hothorn M
油菜素内酯是控制植物生长发育的膜受体激酶Brassinosteroids INSENSITIVE 1 （BRI1）。油菜素内酯结合BRI1富亮氨酸重复序列（LRR）结构域诱导体细胞胚胎发生受体激酶（SERK）家族共受体异聚化。这个过程允许BRI1和SERK的胞质激酶结构域相互作用，反式磷酸化并相互激活。在这里，我们报告了BRI1激酶结构域在其活化形式和与核苷酸复合物中的晶体结构。BRI1具有丝氨酸/苏氨酸激酶和酪氨酸激酶的结构特征，为了解植物中双特异性激酶的进化提供了新的思路。Thr1039， Ser1042和Ser1044的磷酸化导致催化活性激活环的形成。将先前确定的丝氨酸/苏氨酸和酪氨酸磷酸化位点映射到结构上，我们分析了它们对油菜素内酯信号传导的贡献。已知基因错义等位基因的位置提供了对BRI1激酶机制的详细了解，而我们的分析与先前报道的鸟苷酸环化酶活性不一致。我们在激酶的c端叶上发现了一个蛋白质相互作用表面，并证明分离的BRI1， SERK2和SERK3细胞质片段在溶液中形成同型二聚体，并且具有弱的异聚倾向。我们提出了一个模型，其中BRI1和SERK外结构域的异源二聚化使它们的细胞质激酶结构域具有催化能力，这种相互作用可以由BRI1抑制剂蛋白BKI1调节。
Brassinosteroids, which control plant growth and development, are sensed by the membrane receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1). Brassinosteroid binding to the BRI1 leucine-rich repeat (LRR) domain induces heteromerisation with a SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK)-family co-receptor. This process allows the cytoplasmic kinase domains of BRI1 and SERK to interact, trans-phosphorylate and activate each other. Here we report crystal structures of the BRI1 kinase domain in its activated form and in complex with nucleotides. BRI1 has structural features reminiscent of both serine/threonine and tyrosine kinases, providing insight into the evolution of dual-specificity kinases in plants. Phosphorylation of Thr1039, Ser1042 and Ser1044 causes formation of a catalytically competent activation loop. Mapping previously identified serine/threonine and tyrosine phosphorylation sites onto the structure, we analyse their contribution to brassinosteroid signaling. The location of known genetic missense alleles provide detailed insight into the BRI1 kinase mechanism, while our analyses are inconsistent with a previously reported guanylate cyclase activity. We identify a protein interaction surface on the C-terminal lobe of the kinase and demonstrate that the isolated BRI1, SERK2 and SERK3 cytoplasmic segments form homodimers in solution and have a weak tendency to heteromerise. We propose a model in which heterodimerisation of the BRI1 and SERK ectodomains brings their cytoplasmic kinase domains in a catalytically competent arrangement, an interaction that can be modulated by the BRI1 inhibitor protein BKI1.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
11.4
作者：
Hubbard, SR
通讯作者：
Hubbard, SR
影响因子：
7.4
作者：
Clouse, SD;Langford, M;McMorris, TC
通讯作者：
McMorris, TC
影响因子：
7.4
作者：
Bucherl, Christoph A.;van Esse, G. Wilma;de Vries, Sacco C.
通讯作者：
de Vries, Sacco C.
影响因子：
2.9
作者：
Hekmat-Nejad, Mohammad;Cai, Terrence;Swinney, David C.
通讯作者：
Swinney, David C.